Another reason why I prefer grips rather than an allen key is I can clamp on the bolt and turn it with one finger without fear of dropping it. As long as the bolt is still partially in the tree, the grips ain't gonna fall to the ground. Sometimes we might be in an awkward position on the tree and holding an allen key with gloves or cold hands can be clumsy. And don't forget the key has to be aligned and seated perfectly in the cap screw which may not always be easy under certain conditions. And grips will never round off like allen keys can do.
With an allen key, you better have a firm hold on it because if you drop that little wrench, you probably won't find it in leaves or low light. I won't lose those grips if I accidentally drop them, which probably won't happen anyway.
The only advantage that an allen key has over the grips is it's smaller in the pack, but those little grips are tiny. Look at them compared to that 6" bolt in the pic.
